<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <h1>今天在上课</h1>
    <h2>明天不上课</h2>
    <button type="button">
        复制
    </button>
    <script src="jquery.js"></script>
    <script>
        $('button').on('click',function(){
            $('h2').clone().appendTo('body');
        });
    </script>
</body>
</html>